<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>my css</title>
    <link rel="stylesheet" href="mycss.css">
</head>
<body>
<p class="c1">这是一行文字c1</p>
<p class="c2">这是一行文字c2</p>
<p class="c3">这是C3，<span id="i1">i1大小</span><span id="i2">i2大小</span></p>

</body>
</html>